Outbreak Investigations of Foodborne Illness

1. Outbreak Investigations of Foodborne Illness Sherri A. McGarry U.S. Food and Drug Administration Center for Food Safety & Applied Nutrition Office of Food Defense, Communication & Emergency Response

2. Vegetables Seafood Chicken Dietary supplements Infant formula Frozen pizza with extra pepperoni USDAFDA √ √ √ √ √ √ FDA & USDA:Which agency regulates these products? FDA regulates foods(except meat, poultry, and some egg products), food and color additives, cosmetics, dietary supplements, infant formula

3. Outbreaks– FDA regulated products 1996 – 2008: • Dairy 21 • Eggs 207 • Proc Foods 37 • Produce 77 • Seafood 114 • Sprouts 27

4. Illnesses – FDA regulated foods 1996-2008: • Dairy 349 • Eggs 6609 • Proc Foods 3684 • Produce >9000 • Seafood 2819 • Sprouts 1633

5. Fresh Produce Outbreaks • Tomatoes Salmonella • Leafy Greens E. coli O157 • Cantaloupe Salmonella • Hot peppers Salmonella • Herbs Cyclospora, E. coli O157, Shigella • Raspberries Cyclospora • Green Onions Hepatitis A • Mango Salmonella

6. FDA’s Role inOutbreak Investigations • Investigation and coordination in multi-state outbreaks • Review epidemiological, laboratory, and environmental data • Tracebacks of implicated foods • Farm investigations • Removal of implicated products from commerce • Alert consumers • Lab assistance • Evaluate data to identify trends and develop policy, guidance, and/or regulations to prevent future outbreaks Requires teamwork!

7. Teamwork among scientists • Types of scientists needed: • Microbiologists • Laboratory scientists • Epidemiologists • Environmental sanitarians • Veterinarians • Food technologists • Toxicologists • Others – physicians, biologists, agriculturists, etc.

8. Anatomy of an Outbreak investigation Disease Surveillance Epidemiological investigation Laboratory Analysis Environmental investigation Traceback / traceforward Farm / Processor investigation

9. 1. Disease Surveillance • Why do we conduct surveillance of disease and investigate outbreaks? • Identify illnesses and potential outbreaks • Prevent additional illnesses • Identify causes to prevent future illnesses and outbreaks • Who is involved in surveillance? • Federal agencies – CDC, FDA, USDA, EPA • Laboratories • Local and state public health departments Science at work→ Epidemiologists, Physicians,Public Health Officials, Veterinarians, Lab scientists

10. Surveillance and Reporting Illness exposures in the general population Person becomes ill Person seeks medical care/reports illness to HD Specimen obtained Lab tests for pathogen Culture confirmed case Illness reported to HD and CDC

11. How are multi-state foodborne outbreaks recognized? Electronic Foodborne Outbreak Reporting System (eFORS) Database of reports of foodborne disease outbreaks submitted through the internet by local or state health departments PulseNet Database of molecular subtyping (or “fingerprinting”) of bacteria by pulsed-field gel electrophoresis (PFGE) submitted by a national network of laboratories

12. Why does it take so long?

13. 2. Epidemiological investigation • State and local public health officials – collect case information and evaluating data • Determine epidemiologic associations • Case interview information • Attack rates of illness by food type • Test hypothesis → case control study • Interpreting statistical significance • Implicate the food causing illness

14. 3. Laboratory Analysis • Lab testing • Clinical samples • Food samples • Environmental samples • Match clinical results to food product and/or environmental results Science at work→ Microbiologists, Chemists, Toxicologists, Lab scientists

15. Detecting outbreaks • Lab tools • Standard methods to detect pathogens • National database and historical patterns • PFGE • PHLIS – Public Health Laboratory Information System • Electronic reporting system for Salmonella and Shigella human isolates • statistical algorithm designed to detect unusual clusters of isolates of Salmonella infection

16. Detecting outbreaks - Lab • Lab associations • Clustering in time of cases • Same genus and species • Same DNA fingerprint • Between cases and between cases and food • Unusual spikes in illness

17. 4. Environmental investigation Best case scenario: • The epidemiologic investigation helps guide the environmental investigation including areas to focus collection and testing of environmental/product samples However…. • Product samples may no longer be available • Changes likely have occurred in environment Science at work→ Environmental Sanitarians, Epidemiologists, Food technologists, Microbiologists

18. State and local response: Food preparation review Interview food workers Determine if time, temperature abuse or cross-contamination occurred Collect samples Collect records Federal response: Traceback (records) Source investigations along the distribution chain Determine if contamination occurred at that point Collect samples Identify common source Environmental investigation

19. 5. Traceback Epi and/or lab evidence implicates a food Track food item back through the distribution chain to a common source Investigate

21. Zoonotic Salmonella E. coli O157:H7 Campylobacter Human Shigella Hepatitis A virus Norovirus Cyclospora 6. Farm investigation Know your pathogen!

22. Sources of Contamination • Multiple modes: • Soil • Water • Workers • Animals • Everything is • connected! Science at work→ Water Specialists, Agriculturists, Wildlife Experts, Microbiologists

23. FARM INVESTIGATIONS

24. Potential Sources of Contamination: Ponds Animals Equipment Worker Hygiene

25. Reality Check • Seldom do we find the “smoking gun” Why not? • Delay between when the outbreak was detected and when consumers ate the contaminated food • Conditions at the source are not the same as when contamination occurred • Finding the pathogen is difficult • All of the above

26. Case Study…

27. Be the Detective!Contamination at the Farm: Salmonella Saintpaul Spring/Summer 2008

29. Early Sequence of Events • Late May - CDC gave FDA an early alert of Salmonella Saintpaul illnesses in NM & TX • tomatoes a likely vehicle • CDC notifies FDA that tomatoes implicated • FDA initiates traceback investigation • June 3 – Consumer advisory for NM & TX – raw red round and roma/plum tomatoes

30. What to Trace? • Select geographically diverse to triangulate • Prefer cluster vs sporadic case traceback • No clusters so select cases with the best: • Exposure info, receipts to document dates, good food historians, etc • FDA and CDC collaborate to identify best cases to trace

31. Traceability Challenges • Lack of rapid connectivity • Lack of unique identifier • Repacking • Co-mingling • Addresses, ship and reciept dates • Packaging (ie. cases) gone • Produce no longer available • Producing states importing as well

32. Sequence of Events - distribution • Intelligence gathering: • Early outreach to industry on distribution patterns • Industry provides general harvest info • USDA, academic, FDA imports data • Epi suggests consumers nationwide at risk • Early traceback info support • June 7 - Consumer advisory expanded from NM and TX to nationwide not to eat raw red round and roma/plum tomatoes

33. Findings… • Tomatoes shipped from FL to Idaho • Transportation costs may not be as much of a factor as originally thought • Transition time for harvest • Key production areas - FL and MX • Tomatoes in high demand, quick turnaround, unusual market and distribution patterns

34. Responding to an Evolving Picture • No single common convergence on tomato traceback – Florida and Mexico • Several firms appear more than once • Are the problems with traceability making it impossible to find the convergence? • Indications, but no statistical association of other ingredients causing illness • Comparing ingredients of suspect menu items among clusters • Tough to trace guacamole and salsa

35. Stepped Up FDA Actions • Tomato farm investigations – FL & MX • Increased border sampling of multiple produce items • Cilantro, tomatoes, peppers, basil • Sampling assignment covering all points in the chain • Activation of FERN, state assistance for testing

36. Is it tomatoes?More than on vehicle? • MN finds statistical association with jalapeno pepper • FDA initiates pepper & Serrano tracebacks • FDA & CDC face-to-face collaboration at Emergency Operations Centers • FDA outreach to industry for pepper harvest info, geographic, distribution info, production and packing practices

37. FDA Pepper Product Investigations • Initiate hot pepper traceback • Initial traceback lead only to Mexico • FDA investigation team sent to MX

38. More pieces of the puzzle • Investigations find issues at multiple points in distribution chain in MX • June 21 - Positive jalapeno sample of outbreak strain collected at distribution center in McAllen, TX

39. FDA IMPORT ALERTS Due to the presence of Salmonella • IMPORT ALERT #99-23, "DETENTION WITHOUT PHYSICAL EXAMINATION OF RAW FRESH FRUITS AND VEGETABLES FROM LISTED MANUFACTURERS, SHIPPERS, AND/OR GROWERS DUE TO THE PRESENCE OF PATHOGENIC CONTAMINATION", ATTACHMENT - 7/30/08 • Posted on FDA’s website

40. Some Figures… • 447 Investigations by FDA and State Partners • 244 Firms visited for traceback investigations • Over 30 FDA field assignments • Samples – Product and environmental • Distributors, repackers, packing, farms • FDA teams in MX: 11 investigations

41. SAMPLE RESULTS AS OF 8/5/08 • FDA: 482 total samples • (sample = multiple subs not one) • 34 Salmonella positive • 3 Salmonella Saintpaul matches • FERN: 199 total samples • 13Salmonella positive • 1 Salmonella Saintpaul not match

42. Stayed tuned for Peppers...

43. Lessons Learned • Lessons learned in all areas: • Communication • Response • Investigations • epi • Intactions among state and feds • Value of increased environmental sampling • Implemented in recent outbreaks

44. Conclusions • Science plays a major role in detecting outbreaks and investigating the source of contamination in foodborne outbreaks • Understanding how contamination occurred is critical in developing measures to minimize ongoing outbreaks and prevent future ones • Consumers, government, academia, and industry all play a vital role in protecting public health

45. Resources • www.fda.gov • Bad bug book, food safety, press releases on outbreaks, education, and more • www.cdc.gov • PulseNet, surveillance, pathogens, education, and more • www.foodsafety.gov